The conversion of perhydropolysilazane(PHPS)to silica at low temperature is beneficial for its application on thermally vulnerable substrates.In this work,it is demonstrated that(3-aminopropyl)triethoxysilane(APTES)ha...The conversion of perhydropolysilazane(PHPS)to silica at low temperature is beneficial for its application on thermally vulnerable substrates.In this work,it is demonstrated that(3-aminopropyl)triethoxysilane(APTES)has high catalytic efficiency for the low temperature conversion of PHPS and the catalytic mechanism of APTES was suggested.The influence of temperatu re and humidity on the catalytic conversion process was investigated,and it was found that PHPS can be rapidly converted to silica in 10 min at 80℃with relative humidity of 90%.The achieved silica is mainly composed of SiNO_(3)/SiO_(3)OH and SiO_(4)structure with O/Si of 1.74 and N content of 1%.As an approach to prepare inorganic coating,the low-temperature conversion method achieves a silica coating with low volume shrinkage of 0.86%,low roughness of R_(a)=0.293 nm,high nanoindentation hardness of 3.62 GPa and modulus of 30.06 GPa,which exhibits high potentials as protective coating for va rious materials even those vulnerable to high temperature.展开更多
In order to modify the interface, Si ON coating was introduced on the surface of silicon nitride fiber by perhydropolysilazane conversion method. Si-3N4f/SiO2 and Si-3N4f/Si ONc/SiO2 composites were prepared by sol-ge...In order to modify the interface, Si ON coating was introduced on the surface of silicon nitride fiber by perhydropolysilazane conversion method. Si-3N4f/SiO2 and Si-3N4f/Si ONc/SiO2 composites were prepared by sol-gel method to explore the influence of Si ON coating on the mechanical properties of composites.The results show that with the protection of Si ON coating, Si-3N4fiber enjoys a strength increase of up to 24.1% and Si-3N4f/Si ONc/SiO2 composites have a tensile strength of 170.5 MPa and a modulus of26.9 GPa, respectively. After 1000℃ annealing in air for 1 h, Si-3N4f/Si ONc/SiO2 composites retain 65.0%of their original strength and show a better toughness than Si-3N4f/SiO2 composites. The improvement of mechanical properties is attributing to the healing effect of Si ON coating as well as its intermediate coefficient of thermal expansion between Si-3N4fiber and SiO2 matrix.展开更多
All inorganic CsPbI_(3)perovskite solar cells(PSCs)have emerged as disruptive photovoltaic technology owing to their admirable photoelectric properties and the non-volatile active layer.However,the phase instability a...All inorganic CsPbI_(3)perovskite solar cells(PSCs)have emerged as disruptive photovoltaic technology owing to their admirable photoelectric properties and the non-volatile active layer.However,the phase instability against moisture severely limits the fabrication environment for the high-efficiency devices,breaking through the confinement region to achieve scalable manufacturing has been the primary issue for future commercialization.Here,we develop a curing-anti-solvent strategy for fabricating high-quality and stable black-phase CsPbI_(3)perovskite films in ambient air by introducing an inorganic polymer perhydropolysilazane(PHPS)into methyl acetate to form anti-template agent.The cross-linked PHPS reduces moisture erosions while the hydrolyzate silanol network(–Si(OH)_(4)^(–))controls the perovskite crystal growth by forming Lewis adducts with PbI_(2)during the fabrication.The polycondensation adduct of Si–O–Si/Si–O–Pb strongly binds to CsPbI_(3)grains as a shield layer to hamper phase transition.Using the inorganic CsPbI_(3)perovskite thin-film with PHPS-modified anti-solvent processing as the light absorber,the n–i–p planar solar cell achieved an efficiency of 19.17%under standard illumination test conditions.More importantly,the devices showed excellent moisture stability,retaining about 90%of the initial efficiency after 1000 h under 30%RH.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21872152)Guangdong Natural Science Foundation(No.2019A1515111028)Xiejialin Foundation in the Institute of High Energy Physics(No.E15466U210)。
文摘The conversion of perhydropolysilazane(PHPS)to silica at low temperature is beneficial for its application on thermally vulnerable substrates.In this work,it is demonstrated that(3-aminopropyl)triethoxysilane(APTES)has high catalytic efficiency for the low temperature conversion of PHPS and the catalytic mechanism of APTES was suggested.The influence of temperatu re and humidity on the catalytic conversion process was investigated,and it was found that PHPS can be rapidly converted to silica in 10 min at 80℃with relative humidity of 90%.The achieved silica is mainly composed of SiNO_(3)/SiO_(3)OH and SiO_(4)structure with O/Si of 1.74 and N content of 1%.As an approach to prepare inorganic coating,the low-temperature conversion method achieves a silica coating with low volume shrinkage of 0.86%,low roughness of R_(a)=0.293 nm,high nanoindentation hardness of 3.62 GPa and modulus of 30.06 GPa,which exhibits high potentials as protective coating for va rious materials even those vulnerable to high temperature.
基金the financial support from the National Natural Science Foundation of China (Grant No. 51702361)the Natural Science Foundation of Hunan Province (Grant No. 2017JJ3353)
文摘In order to modify the interface, Si ON coating was introduced on the surface of silicon nitride fiber by perhydropolysilazane conversion method. Si-3N4f/SiO2 and Si-3N4f/Si ONc/SiO2 composites were prepared by sol-gel method to explore the influence of Si ON coating on the mechanical properties of composites.The results show that with the protection of Si ON coating, Si-3N4fiber enjoys a strength increase of up to 24.1% and Si-3N4f/Si ONc/SiO2 composites have a tensile strength of 170.5 MPa and a modulus of26.9 GPa, respectively. After 1000℃ annealing in air for 1 h, Si-3N4f/Si ONc/SiO2 composites retain 65.0%of their original strength and show a better toughness than Si-3N4f/SiO2 composites. The improvement of mechanical properties is attributing to the healing effect of Si ON coating as well as its intermediate coefficient of thermal expansion between Si-3N4fiber and SiO2 matrix.
基金support from the Natural Science Foundation of China(no.22005071)the Natural Science Special(Special Post)Research Foundation of Guizhou University(no.2020-13)The cultivation programs Research Foundation of Guizhou University(no.2019-64).
文摘All inorganic CsPbI_(3)perovskite solar cells(PSCs)have emerged as disruptive photovoltaic technology owing to their admirable photoelectric properties and the non-volatile active layer.However,the phase instability against moisture severely limits the fabrication environment for the high-efficiency devices,breaking through the confinement region to achieve scalable manufacturing has been the primary issue for future commercialization.Here,we develop a curing-anti-solvent strategy for fabricating high-quality and stable black-phase CsPbI_(3)perovskite films in ambient air by introducing an inorganic polymer perhydropolysilazane(PHPS)into methyl acetate to form anti-template agent.The cross-linked PHPS reduces moisture erosions while the hydrolyzate silanol network(–Si(OH)_(4)^(–))controls the perovskite crystal growth by forming Lewis adducts with PbI_(2)during the fabrication.The polycondensation adduct of Si–O–Si/Si–O–Pb strongly binds to CsPbI_(3)grains as a shield layer to hamper phase transition.Using the inorganic CsPbI_(3)perovskite thin-film with PHPS-modified anti-solvent processing as the light absorber,the n–i–p planar solar cell achieved an efficiency of 19.17%under standard illumination test conditions.More importantly,the devices showed excellent moisture stability,retaining about 90%of the initial efficiency after 1000 h under 30%RH.
